Suppressing your telephone number

You can suppress your telephone number when making calls so that it is not transmitted to the party you are calling. That way the party you are calling does not see your number in the display of their telephone. This function is called "CLIR" (Calling Line Identification Restriction). You can either suppress your caller ID for a single call or permanently suppress it for all calls.

Requirements

Your telephony provider must have enabled Calling Line Identification Restriction (CLIR) on a call-by-call basis for your telephone line.

1 Enabling CLIR on a case-by-case basis (only for a single call)

You can suppress your caller ID for a single call. Your caller ID will be transmitted again when you make subsequent calls:

Configuring a telephone to use the keypad function

Keypad sequences are strings of characters and digits that can be used to enable or disable functions. You can use keypad sequences right away with telephones, such as FRITZ!Fon C5, that are registered with the base station of your FRITZ!Box. If you are using a telephone that is connected to the "FON S0" port or a cordless telephone that is not registered with the FRITZ!Box's base station, you must first set up the keypad function:

Configure the devices so that you can send keypad sequences (sequences of symbols and digits, such as *121#) and dial special characters such as * and # with them. With many telephones, you can use the menu "Operation at a PBX > Dialing options > Dial * and #" to configure this.

Suppressing your telephone number for the next call

When making a telephone call, dial the prefix *31# before the number you would like to call. Your caller ID will then be suppressed for this call.

Example:In order to suppress your number when calling the telephone number 0301234, dial *31#0301234.

2 Permanently suppressing your caller ID (for all calls)

You can also permanently suppress your caller ID for all calls. To do so, you must enable CLIR (Calling Line Identification Restriction) in the FRITZ!Box or your telephone. The procedure depends on the type of telephone you are using:

Note:If you have enabled permanent suppression of the caller ID, you can still transmit your caller ID for one call. To do so, simply dial the prefix #31# before the actual number, for example #31#0301234. Your caller ID will now be transmitted only for this call and suppressed for the following calls.